1. Field of the Invention
The present invention relates generally to medical apparatus and methods. More particularly, the present invention relates to a method and apparatus for capturing, fragmenting, and removing urinary stones from the kidney or bladder.
Urinary tract endoscopy, a minimally invasive procedure for removing urinary stones that are present in the bladder, ureter, or kidney, may be performed in several ways. A large viewing scope, referred to as a cystoscope, is advanced from the urethra into the bladder. When necessary, a smaller ureteroscope is further advanced from the bladder, through the ureter, and into the kidney. Alternatively, a nephroscope entering through a percutaneous tract into the kidney, may be used in the kidney and upper urinary tract. In each of these protocols, endoscopes carry either an optical element or optical fiber bundle which in some cases are steerable so that individual stones may be observed, captured, and removed from the kidney and bladder. The endoscopes carry a working channel for the introduction of tools to the distal end of the device. The working channel in a ureteroscope, however, has a very small diameter, due to the very small size of the device itself, typically limiting tool use to one small tool at a time. Optionally, the stones may be fragmented using laser or other energy, and the intact stone and/or fragments may be removed using a deployable basket advanced through a working channel of the endoscope.
Endoscopic stone treatment is particularly difficult to perform in the bladder and kidney where the stones or stone fragments may be mobile and are present in a large open volume and thus are often difficult to capture. While the stones may be captured using a basket or other tools under direct visualization, steering the scope and firmly capturing the stone is problematic, particularly if the stone is mobile and suspended within the open volume. Moreover, if the stone is fragmented with energy, capturing the many stone fragments which disperse throughout the volume and can be even more difficult and time consuming.
For these reasons, it would be desirable to provide improved and alternative apparatus and protocols for the ureteroscopic treatment and removal of stones from the urinary system, particularly the kidney and bladder. Such systems and protocols will preferably be compatible with many or all conventional endoscopes which are commercially available. Desirably, the apparatus and protocols will facilitate capturing of the stones within the open volumes of the kidney and bladder, will allow for energy-based fragmentation of the stones while they remain captured, and will contain most or all of the stone fragments resulting from the fragmentation. The apparatus and protocols would preferably reduce the need to use the working channel of the endoscope, making the working channel available for an energy source or use in new protocols. At least some of these objectives will be met by the inventions described below.
2. Background of the Background Art
Commonly owned, copending application Ser. Nos. 10/886,886; 11/777,515; 12/041,241; and 12/269,739 describe conformable structures which are deployable in the urethra and ureter and which may be used to entrap stones during lithotripsy. Dr. Bogdan Petrut has filed a Romanian Patent Application describing a stone capture device for attaching to a ureteroscope to capture and draw stones into a sheath for containing the stones while delivering laser energy to break up the stones. See also U.S. Pat. Nos. 3,760,810; 3,870,048; 4,222,308; 4,257,420; 4,471,766; 4,735,194; 5,423,834; 5,507,797; 6,099,535; 6,645,195; 6,869,395; 7,204,804; and 7,223,230. U.S. Patent Publication No. US2006/0116693 describes a stone capture device intended for use in lithotripsy treatment. The RothNet® foreign body retrieval device is described at http://www.usendoscopy.com/foreignbody.php.